OsCommerce can be adjusted however you like.
ts feature packed out-of-the-box installation allows store owners to setup, run, and maintain their online stores with minimum effort.
Everything you need to get started in selling physical and digital goods over the internet, from the Catalog frontend that is presented to your customers, to the Administration Tool backend that completely handles your online store data.

Take a look at this example store:
http://helpinghost.support-help.com/catalog/

and this example store administrator ( here you add products and change settings):
http://helpinghost.support-help.com/admin/index.php